Inter-Scanner Variability and Evaluation of T2-FLAIR Harmonization in Alzheimer’s Neuroimaging

Motivation: Standardized protocols for multi-center imaging studies like ADNI attempt to harmonize imaging data, but evaluating image quality is essential to assess differences between sites. Goal(s): To highlight visual and quantitative differences in ADNI-protocol T2-FLAIR images across scanner manufacturers. Approach: ADNI3 T2-FLAIR images from three manufacturers were compared via gray matter/white matter contrast ratio (GM/WM). Additionally, we compared the ADNI-protocol and a GM/WM optimized T2-FLAIR sequence in a single scan session for 3 subjects. Results: ADNI3 GM/WM ratio was significantly different across manufacturers, with GE having the lowest GM/WM contrast. For this manufacturer, we found that a GM/WM optimized T2-FLAIR can improve inter-scanner harmonization. Impact: T2-FLAIR is an instrumental imaging sequence to visualize gray-white matter contrast and white matter abnormalities. However, inter-scanner variability may hinder analysis involving multi-site imaging datasets. Thus, we evaluated protocol changes that can improve harmonization of T2-FLAIR images across scanners.